Dyeing composition for keratinous fibers comprising a particular dicationic diazo dye

ABSTRACT

The present disclosure relates to a novel dyeing composition for dyeing human keratinous fibers, such as hair, comprising at least one dicationic diazo dye of formula (I):  
     [W 1 —N═N—W 2 —W 3 —(W 4 —W 5 ) p -] 2 -L   Formula (I)  
     as well as the process for dyeing hair using same. Certain compounds of formula (I) are also disclosed herein.

[0001] The invention relates to a novel dye composition for dyeing humankeratin fibers, in particular the hair, comprising a particulardicationic diazo dye, and also to the process for dyeing keratin fibersusing such a composition. The invention also relates to novel dicationicdiazo dyes.

[0002] It is known practice to dye keratin fibers, and in particularhuman hair, with dye compositions containing oxidation dye precursors,which are generally known as oxidation bases, such as ortho- orpara-phenylenediamines, ortho- or para-aminophenols and heterocycliccompounds. These oxidation bases are colorless or weakly coloredcompounds, which, when combined with oxidizing products, give rise tocolored compounds by a process of oxidative condensation.

[0003] It is also known that the shades obtained with these oxidationbases may be varied by combining them with couplers or colorationmodifiers, the latter agents being chosen especially from aromaticmeta-diamines, meta-aminophenols, meta-diphenols and certainheterocyclic compounds such as indole compounds.

[0004] The variety of molecules used as oxidation bases and couplersallows a wide range of colors to be obtained.

[0005] This process of oxidation dyeing consists in applying to thekeratin fibers oxidation bases or a mixture of oxidation bases and ofcouplers with an oxidizing agent, for example aqueous hydrogen peroxidesolution, leaving the application on the fibers, and then rinsing thefibers. The colorations resulting therefrom are permanent, strong andfast with respect to external agents, especially light, bad weather,washing, perspiration and rubbing. Generally applied at basic pH, dyeingand simultaneous lightening of the fiber may be obtained, which isreflected in practice by the possibility of obtaining a final colorationthat is lighter than the original color. In addition, lightening of thefiber may have the advantageous effect of producing a unified color inthe case of gray hair, and, in the case of naturally pigmented hair, ofbringing out the color, i.e. of making it more visible.

[0006] It is also known practice to dye keratin fibers by direct dyeing.The process conventionally used in direct dyeing consists in applying tothe keratin fibers direct dyes, which are colored and coloring moleculesthat have affinity for the fibers, leaving the dyes on the fibers, andthen rinsing the fibers.

[0007] It is known practice, for example, to use direct dyes belongingto the nitrobenzene, anthraquinone, nitropyridine, azo, indoamine, azineor triarylmethane class.

[0008] The colorations resulting therefrom are particularly chromaticcolorations, that are temporary or semi-permanent since the nature ofthe interactions binding the direct dyes to the keratin fiber, and theirdesorption from the surface and/or the core of the fiber are responsiblefor their poor dyeing power and their poor resistance to washing or toperspiration. These direct dyes are also generally light-sensitive dueto the poor resistance of the chromophore with respect to photochemicalattack, leading over time to fading of the coloration of the hair. Inaddition, their light sensitivity is dependent on their uniformdistribution or distribution as aggregates in the keratin fiber.

[0009] It is known practice to use direct dyes in combination withoxidizing agents. However, direct dyes are generally sensitive to theaction of oxidizing agents such as aqueous hydrogen peroxide solution,and reducing agents such as sodium bisulfite, which makes it generallydifficult to use them in compositions for lightening direct dyeing basedon aqueous hydrogen peroxide solution and based on a basifying agent orin oxidation dye compositions in combination with precursors such asoxidation bases or couplers.

[0010] For example, it has been proposed in patent applications FR-1 584965 and JP-062 711 435 to dye the hair with dye compositions based onnitro direct dyes and/or dispersed azo dyes and on ammoniacal aqueoushydrogen peroxide solution, by applying to the hair a mixture of saiddyes and of said oxidizing agent, prepared just before use. However, thecolorations obtained are found to have insufficient resistance anddisappear on shampooing, making the lightening of the hair fiber showthrough. Such a coloration becomes unattractive by changing over time.

[0011] It has also been proposed in patent applications JP-53 95693 andJP-55 022 638 to dye the hair with compositions based on cationic directdyes of oxazine type and on ammoniacal aqueous hydrogen peroxidesolution, by applying to the hair ammoniacal aqueous hydrogen peroxidesolution in a first step, followed by a composition based on the oxazinedirect dye in a second step. This coloration is unsatisfactory becauseit requires a process that is made too slow by the leave-in times of thetwo successive steps. If, besides that, an extemporaneous mixture of theoxazine direct dye with ammoniacal aqueous hydrogen peroxide solution isapplied to the hair, the hair fiber is not colored or at most, avirtually nonexistent coloration is obtained.

[0012] More recently, patent application FR 2 741 798 has disclosed dyecompositions containing direct dyes comprising at least one quaternizednitrogen atom of the azo or azomethine type, said compositions being forextemporaneous mixing at basic pH with an oxidizing composition. Thesecompositions make it possible to obtain uniform, resistant and brightcolorations with glints. However, they do not allow keratin fibers to bedyed as strongly as with oxidation dye compositions.

[0013] There is thus a real need to find chromatic direct dyes thatallow keratin fibers to be dyed as strongly as with oxidation dyes,which are just as stable as oxidation dyes to light, which are also fastwith respect to bad weather, washing and perspiration, and which arealso stable enough in the presence of oxidizing and reducing agents tobe able simultaneously to obtain lightening of the fiber either by usinglightening direct compositions containing them, or by using oxidationdye compositions containing them. There is also a real need to finddirect dyes that allow keratin fibers to be dyed to obtain a very widerange of colors, in particular very chromatic colors, not forgetting the“fundamental” shades, for instance, blacks and browns.

[0014] These aims are achieved with the present invention, one subjectof which is a composition for dyeing human keratin fibers, and inparticular the hair, comprising at least one dicationic diazo dye offormula (I) below:

[W₁—N═N—W₂—W₃—(W₄—W₅)_(p)-]₂-L   Formula (I)

[0015] in which

[0016] p=0 or 1,

[0017] W₁ represents a heteroaromatic radical of formulae (II) and (III)below:

[0018] W₂ represents a carbon-based, pyridine-based or pyridazine-basedaromatic group of formula (IV) below:

[0019] W₃ and W₅ represent, independently of each other, a radical—NR₁₄— or an oxygen atom —O—, or a nitrogen atom,

[0020] W₄ represents a saturated or unsaturated, linear or branchedC₁-C₁₆ hydrocarbon-based chain, which can form one or more 3- to6-membered carbon-based rings, one or more carbon atoms of thecarbon-based chain of which may be replaced with an oxygen, nitrogen orsulfur atom or with an SO₂ group, and the carbon atoms of which may besubstituted, independently of each other, with one or more halogenatoms, W₄ not comprising a peroxide bond or diazo or nitroso radicals; apiperazine ring; a group of formula (V) below:

[0021] in which formulae (II), (III), (IV) and (V):

[0022] X₁ represents a nitrogen atom or a radical CR₅

[0023] X₂ represents a nitrogen atom or a radical CR₆

[0024] X₃ represents a nitrogen atom or a radical CR₁₇

[0025] X₄ represents a nitrogen atom or a radical CR₁₈

[0026] Z₁ represents an oxygen or sulfur atom or a radical NR₈,

[0027] Z₂ represents a nitrogen atom or a radical CR₉,

[0028] it being understood that formula (II) does not denote animidazolium ring, i.e. (Z₁, Z₂) is different than (NR₈, CR₉),

[0029] Z₃ represents a nitrogen atom or a radical CR₁₂,

[0030] Z₄ represents a nitrogen atom or a radical CR₁₃,

[0031] the bond a of the 5-membered cationic ring of formula (II) islinked to the azo group of formula (I),

[0032] the bond b of the 6-membered cationic ring of formula (III) islinked to the azo group of formula (I),

[0033] when p=0,

[0034] then L represents a linear or branched, saturated C₁-C₁₆hydrocarbon-based chain, which can form one or more 3- to 6-memberedcarbon-based rings, one or more carbon atoms of the carbon-based chainof which may be replaced with an oxygen, nitrogen or sulfur atom or withan SO₂ group, and the carbon atoms of which may be substituted,independently of each other, with one or more halogen atoms; L notcomprising a peroxide bond or diazo or nitroso radicals,

[0035] when p=1,

[0036] then L represents a saturated or unsaturated, linear or branchedC₁-C₁₆ hydrocarbon-based chain, which can form one or more 3- to6-membered carbon-based rings, one or more carbon atoms of thecarbon-based chain of which may be replaced with an oxygen, nitrogen orsulfur atom or with an SO₂ group, and not comprising a peroxide bond ordiazo or nitroso radicals,

[0037] R₃, R₄, R₅, R₆, R₇, R₉, R₁₀, R₁₁, R₁₂, R₁₃, R₁₄, R₁₅, R₁₆, R₁₇and R₁₈ represent, together or independently of each other, a hydrogenatom, a saturated or unsaturated, linear or branched C₁-C₁₆hydrocarbon-based chain, which can form one or more 3- to 6-memberedcarbon-based rings, one or more carbon atoms of the carbon-based chainof which may be replaced with an oxygen, nitrogen or sulfur atom or withan SO₂ group, and the carbon atoms of which may be substituted,independently of each other, with one or more halogen atoms; R₃, R₄, R₅,R₆, R₇, R₉, R₁₀, R₁₁, R₁₂, R₁₃, R₁₄, R₁₅, R₁₆, R₁₇ and R₁₈ notcomprising a peroxide bond or diazo or nitroso radicals,

[0038] R₃ with R₄, R₇ with R₉, R₁₀ with R₁₁, R₁₂ with R₁₃ and R₁₅ withR₁₆ may form a carbon-based aromatic ring, such as a phenyl,

[0039] X is an organic or mineral anion.

[0040] According to the invention, when it is indicated that one or moreof the carbon atoms of the hydrocarbon-based chain defined for theradicals L, R₃, R₄, R₅, R₆, R₇, R₉, R₁₀, R₁₁, R₁₂, R₁₃, R₁₄, R₁₅, R₁₆,R₁₇ and R₁₈ may be replaced with an oxygen, nitrogen or sulfur atom orwith an SO₂ group, and/or when these hydrocarbon-based chains areunsaturated, this means that the following conversions may be performed,for example:

[0041] In particular the term “branched hydrocarbon-based chain” means achain that can form one or more 3- to 6-membered carbon-based rings. Theterm “unsaturated hydrocarbon-based chain” means a chain that maycomprise one or more double bonds and/or one or more triple bonds, thishydrocarbon-based chain possibly leading to aromatic groups.

[0042] X is an organic or mineral anion chosen, for example, from ahalide such as chloride, bromide, fluoride or iodide; a hydroxide; asulfate; a hydrogen sulfate; a (C₁-C₆)alkyl sulfate, for example amethyl sulfate or an ethyl sulfate; an acetate; a tartrate; an oxalate;a (C₁-C₆)alkylsulfonate such as methylsulfonate; an arylsulfonate thatis unsubstituted or substituted with a C₁-C₄ alkyl radical, for instancea 4-tolylsulfonate.

[0043] R₃, R₄, R₅, R₆, R₁₀, R₁₁, R₁₂, R₁₃, R₁₅, R₁₆, R₁₇ and R₁₈preferably represent, independently of each other, a hydrogen atom; alinear or branched C₁-C₄ alkyl radical, optionally substituted with oneor more radicals chosen from hydroxyl, C₁-C₂ alkoxy, C₂-C₄(poly)hydroxyalkoxy, amino, C₁-C₂ (di)alkylamino, carboxyl and sulfonicradicals; a phenyl radical optionally substituted with one or moreradicals chosen from hydroxyl, C₁-C₂ alkoxy, C₂-C₄ (poly)hydroxyalkoxy,amino, C₁-C₂ (di)alkylamino, carboxyl and sulfonic radicals or a halogenatom such as chlorine, fluorine or bromine; a carboxyl radical; asulfonylamino radical; a sulfonic radical; a C₁-C₂ alkoxy radical; aC₂-C₄ (poly)hydroxyalkoxy radical; an amino radical; a C₁-C₂(di)alkylamino radical; a C₂-C₄ (poly)hydroxyalkylamino radical.

[0044] More preferably, R₃, R₄, R₅, R₆, R₁₀, R₁₁, R₁₂, R₁₃, R₁₅, R₁₆,R₁₇ and R₁₈ represent a hydrogen atom, a C₁-C₄ alkyl radical optionallysubstituted with one or more radicals chosen from hydroxyl, amino andC₁-C₂ (di)alkylamino radicals; a carboxyl radical; a C₁-C₂ alkoxyradical; an amino radical; a C₁-C₂ (di)alkylamino radical; a C₂-C₄(poly)hydroxyalkylamino radical.

[0045] According to one particularly preferred embodiment, R₃, R₄, R₅,R₆, R₁₀, R₁₁, R₁₂, R₁₃, R₁₅, R₁₆, R₁₇ and R₁₈ represent a hydrogen atom,a methyl, phenyl or 2-hydroxymethyl radical, a carboxyl, a methoxy,ethoxy or 2-hydroxyethyloxy radical, or an amino, methylamino,dimethylamino or 2-hydroxyethylamino radical.

[0046] R₇ and R₉ represent, independently of each other, a hydrogenatom; a linear or branched C₁-C₄ alkyl radical optionally substitutedwith one or more radicals chosen from hydroxyl, C₁-C₂ alkoxy, C₂-C₄(poly)hydroxyalkoxy, amino, C₁-C₂ (di)alkylamino, carboxyl and sulfonicradicals; an optionally substituted phenyl radical; a carboxyl radical;a sulfonylamino radical.

[0047] Among these substituents, R₇ and R₉ preferably represent ahydrogen atom, a phenyl radical or a C₁-C₄ alkyl radical optionallysubstituted with one or more radicals chosen from hydroxyl, amino, C₁-C₂(di)alkylamino and carboxyl radicals.

[0048] According to one particularly preferred embodiment, R₇ and R₉preferably represent a hydrogen atom, a methyl, phenyl or2-hydroxymethyl radical or a carboxyl.

[0049] R₁₄ preferably represents a hydrogen atom; a linear or branchedC₁-C₆ alkyl radical, optionally substituted with one or more radicalschosen from hydroxyl, C₁-C₂ alkoxy, C₂-C₄ (poly)hydroxyalkoxy, amino,C₁-C₂ (di)alkylamino, carboxyl and sulfonic radicals; an optionallysubstituted phenyl radical.

[0050] R₁₄ preferably represents a hydrogen atom; a linear or branchedC₁-C₄ alkyl radical, optionally substituted with one or more radicalschosen from hydroxyl, C₁-C₂ alkoxy, amino and C₁-C₂ (di)alkylaminoradicals.

[0051] R₁₄ preferably represents a hydrogen atom; a methyl, ethyl,2-hydroxyethyl, 2-aminoethyl, 2-methoxyethyl, 1-carboxymethyl,2-carboxyethyl or 2-sulfonylethyl radical.

[0052] R₁₄ preferably represents a hydrogen atom; a methyl, ethyl,2-hydroxyethyl or 2-aminoethyl radical.

[0053] R₁, R₂ and R₈ represent a linear or branched C₁-C₈ alkyl radical,optionally substituted with one or more radicals chosen from hydroxyl,C₁-C₂ alkoxy, C₂-C₄ (poly)hydroxyalkoxy, amino, C₁-C₂ (di)alkylamino,carboxyl and sulfonic radicals; an optionally substituted phenylradical.

[0054] Among these substituents, R₁, R₂ and R₈ preferably represent aC₁-C₄ alkyl radical optionally substituted with one or more radicalschosen from hydroxyl, C₁-C₂ alkoxy, amino, C₁-C₂ (di)alkylamino,carboxyl and sulfonic radicals.

[0055] According to one particularly preferred embodiment, R₁, R₂ and R₈preferably represent a methyl, ethyl, 2-hydroxyethyl, 1-carboxymethyl,2-carboxyethyl or 2-sulfonylethyl radical.

[0056] W₁ preferably represents a triazolium, thiazolium or pyridiniumcationic group substituted with the preferred radicals R₁, R₂, R₇, R₁₀,R₁₁, R₁₂ and R₁₃.

[0057] W₂ preferably represents a phenyl or pyridyl group substitutedwith the preferred radicals R₃, R₄, R₅ and R₆.

[0058] W₃ and W₅ preferably represent, independently of each other, agroup —NR₁₄—, with the preferred meanings of R₁₄ .

[0059] W₄ preferably represents a linear or branched C₂-C₆ alkylradical, optionally substituted with one or more radicals chosen fromhydroxyl, C₁-C₂ alkoxy, C₂-C₄ (poly)hydroxyalkoxy, amino, C₁-C₂(di)alkylamino, carboxyl and sulfonic radicals; a phenyl radicaloptionally substituted with one or more radicals chosen from hydroxyl,C₁-C₂ alkoxy, C₂-C₄ (poly)hydroxyalkoxy, amino, C₁-C₂ (di)alkylamino,carboxyl and sulfonic radicals or a halogen atom such as chlorine,fluorine or bromine; a naphthyl radical optionally substituted with oneor more radicals chosen from hydroxyl, C₁-C₂ alkoxy, C₂-C₄(poly)hydroxyalkoxy, amino, C₁-C₂ (di)alkylamino, carboxyl and sulfonicradicals or a halogen atom such as chlorine, fluorine or bromine, or apiperazine radical formed with the two radicals W₃ and W₅.

[0060] W₄ preferably represents a linear or branched C₂-C₄ alkylradical, optionally substituted with one or more hydroxyl radicals; aphenyl radical optionally substituted with one or more radicals chosenfrom hydroxyl, C₁-C₂ alkoxy, C₂-C₄ (poly)hydroxyalkoxy, amino, C₁-C₂(di)alkylamino, carboxyl and sulfonic radicals; a naphthyl radicaloptionally substituted with one or more radicals chosen from hydroxyl,C₁-C₂ alkoxy, C₂-C₄ (poly)hydroxyalkoxy, amino, C₁-C₂ (di)alkylamino,carboxyl and sulfonic radicals, or a piperazine radical formed with thetwo radicals W₃ and W₅.

[0061] W₄ preferably represents an ethyl, propyl, butyl or2-hydroxypropyl radical; a phenyl radical; a naphthyl radical; apiperazine ring formed with the two radicals W₃ and W₅.

[0062] L preferably represents a group chosen from —CO—;—CO—CH₂—CH₂—CO—; —CO—CO—; benzo-1,4-dicarbonyl; ethyl; 1,4-phenyl;triazine; pyrimidine.

[0063] L preferably represents an ethyl or triazine group.

[0064] The concentration of dicationic diazo dye of formula (I) mayrange from 0.001% to 5% by weight approximately, and preferably fromabout 0.05% to 2% by weight, relative to the total weight of the dyecomposition.

[0065] Among the dicationic diazo dyes of formula (I) according to thepresent invention, mention may be made especially of the compoundshaving the following formulae:

[0066] Among these compounds, the ones even more particularly preferredaccording to the invention are those comprising a triazolium ring.

[0067] In the above formulae, Me denotes a CH₃ radical.

[0068] The dye composition in accordance with the invention may alsocontain direct dyes other than those of formula (I), these dyes possiblybeing chosen especially from neutral, acidic or cationic nitrobenzenedirect dyes, neutral, acidic or cationic azo direct dyes, quinone and inparticular neutral, acidic or cationic anthraquinone direct dyes, azinedirect dyes, methine direct dyes, triarylmethane direct dyes, indoaminedirect dyes and natural direct dyes.

[0069] Among the benzenic direct dyes that may be used according to theinvention, mention may be made, in a non-limiting manner, of thefollowing compounds:

[0070] 1,4-diamino-2-nitrobenzene

[0071] 1-amino-2-nitro-4-(β-hydroxyethylamino)benzene

[0072] 1-amino-2-nitro-4-bis(β-hydroxyethyl)aminobenzene

[0073] 1,4-bis(β-hydroxyethylamino)-2-nitrobenzene

[0074] 1-β-hydroxyethylamino-2-nitro-4-bis-(β-hydroxyethylamino)benzene

[0075] 1-β-hydroxyethylamino-2-nitro-4-aminobenzene

[0076]1-β-hydroxyethylamino-2-nitro-4-(ethyl)(β-hydroxyethyl)aminobenzene

[0077] 1-amino-3-methyl-4-β-hydroxyethylamino-6-nitrobenzene

[0078] 1-amino-2-nitro-4-β-hydroxyethylamino-5-chlorobenzene

[0079] 1,2-diamino-4-nitrobenzene

[0080] 1-amino-2-β-hydroxyethylamino-5-nitrobenzene

[0081] 1,2-bis(β-hydroxyethylamino)-4-nitrobenzene

[0082] 1-amino-2-[tris(hydroxymethyl)methylamino]-5-nitrobenzene

[0083] 1-hydroxy-2-amino-5-nitrobenzene

[0084] 1-hydroxy-2-amino-4-nitrobenzene

[0085] 1-hydroxy-3-nitro-4-aminobenzene

[0086] 1-hydroxy-2-amino-4,6-dinitrobenzene

[0087] 1-β-hydroxyethyloxy-2-β-hydroxyethylamino-5-nitrobenzene

[0088] 1-methoxy-2-β-hydroxyethylamino-5-nitrobenzene

[0089] 1-β-hydroxyethyloxy-3-methylamino-4-nitrobenzene

[0090] 1-β,γ-dihydroxypropyloxy-3-methylamino-4-nitrobenzene

[0091] 1-β-hydroxyethylamino-4-β,γ-dihydroxypropyloxy-2-nitrobenzene

[0092] 1-β,γ-dihydroxypropylamino-4-trifluoromethyl-2-nitrobenzene

[0093] 1-β-hydroxyethylamino-4-trifluoromethyl-2-nitrobenzene

[0094] 1-β-hydroxyethylamino-3-methyl-2-nitrobenzene

[0095] 1-β-aminoethylamino-5-methoxy-2-nitrobenzene

[0096] 1-hydroxy-2-chloro-6-ethylamino-4-nitrobenzene

[0097] 1-hydroxy-2-chloro-6-amino-4-nitrobenzene

[0098] 1-hydroxy-6-[bis(β-hydroxyethyl)amino]-3-nitrobenzene

[0099] 1-β-hydroxyethylamino-2-nitrobenzene

[0100] 1-hydroxy-4-β-hydroxyethylamino-3-nitrobenzene.

[0101] Among the azo direct dyes that may be used according to theinvention, mention may be made of the cationic azo dyes described inpatent applications WO 95/15144, WO 95/01772 and EP 714 954, the contentof which forms an integral part of the invention.

[0102] Among these compounds, mention may be made most particularly ofthe following dyes:

[0103] 1,3-dimethyl-2-[[4-(dimethylamino)phenyl]azo]-1H-imidazoliumchloride,

[0104] 1,3-dimethyl-2-[(4-aminophenyl)azo]-1H-imidazolium chloride,

[0105] 1-methyl-4-[(methylphenylhydrazono)methyl]pyridinium methylsulfate.

[0106] Among the azo direct dyes that may also be mentioned are thefollowing dyes described in the Colour Index International 3rd edition:

[0107] Disperse Red 17

[0108] Acid Yellow 9

[0109] Acid Black 1

[0110] Basic Red 22

[0111] Basic Red 76

[0112] Basic Yellow 57

[0113] Basic Brown 16

[0114] Acid Yellow 36

[0115] Acid Orange 7

[0116] Acid Red 33

[0117] Acid Red 35

[0118] Basic Brown 17

[0119] Acid Yellow 23

[0120] Acid Orange 24

[0121] Disperse Black 9.

[0122] Mention may also be made of1-(4′-aminodiphenylazo)-2-methyl-4-[bis(β-hydroxyethyl)amino]benzene and4-hydroxy-3-(2-methoxyphenylazo)-1-naphthalenesulfonic acid.

[0123] Among the quinone direct dyes that may be mentioned are thefollowing dyes:

[0124] Disperse Red 15

[0125] Solvent Violet 13

[0126] Acid Violet 43

[0127] Disperse Violet 1

[0128] Disperse Violet 4

[0129] Disperse Blue 1

[0130] Disperse Violet 8

[0131] Disperse Blue 3

[0132] Disperse Red 11

[0133] Acid Blue 62

[0134] Disperse Blue 7

[0135] Basic Blue 22

[0136] Disperse Violet 15

[0137] Basic Blue 99

[0138] and also the following compounds:

[0139] 1-N-methylmorpholiniumpropylamino-4-hydroxyanthraquinone

[0140] 1-aminopropylamino-4-methylaminoanthraquinone

[0141] 1-aminopropylaminoanthraquinone

[0142] 5-β-hydroxyethyl-1,4-diaminoanthraquinone

[0143] 2-aminoethylaminoanthraquinone

[0144] 1,4-bis(β,γ-dihydroxypropylamino)anthraquinone

[0145] Among the azine dyes that may be mentioned are the followingcompounds:

[0146] Basic Blue 17

[0147] Basic Red 2.

[0148] Among the triarylmethane dyes that may be used according to theinvention, mention may be made of the following compounds:

[0149] Basic Green 1

[0150] Acid Blue 9

[0151] Basic Violet 3

[0152] Basic Violet 14

[0153] Basic Blue 7

[0154] Acid Violet 49

[0155] Basic Blue 26

[0156] Acid Blue 7

[0157] Among the indoamine dyes that may be used according to theinvention, mention may be made of the following compounds:

[0158]2-β-hydroxyethylamino-5-[bis(β-4′-hydroxyethyl)amino]-anilino-1,4-benzoquinone;

[0159]2-β-hydroxyethylamino-5-(2′-methoxy-4′-amino)anilino-1,4-benzoquinone;

[0160]3-N(2′-chloro-4′-hydroxy)phenylacetylamino-6-methoxy-1,4-benzoquinoneimine;

[0161]3-N(3′-chloro-4′-methylamino)phenylureido-6-methyl-1,4-benzoquinoneimine;

[0162]3-[4′-N-(ethylcarbamylmethyl)amino]phenylureido-6-methyl-1,4-benzoquinoneimine.

[0163] Among the natural direct dyes that may be used according to theinvention, mention may be made of lawsone, juglone, alizarin, purpurin,carminic acid, kermesic acid, purpurogallin, protocatechaldehyde,indigo, isatin, curcumin, spinulosin and apigenidin. Extracts ordecoctions containing these natural dyes may also be used, andespecially henna-based poultices or extracts.

[0164] The additional direct dye(s) preferably represent(s) from 0.001%to 20% by weight approximately, and even more preferably from 0.005% to10% by weight approximately, relative to the total weight of theproduct.

[0165] The composition of the invention may also comprise an oxidizingagent. This oxidizing agent may be any oxidizing agent conventionallyused for bleaching keratin fibers. The oxidizing agent is preferablychosen from hydrogen peroxide, urea peroxide, alkali metal bromates,persalts such as perborates and persulfates, peracids and enzymes, amongwhich mention may be made of peroxidases, 2-electron oxidoreductasessuch as uricases, and 4-electron oxigenases such as laccases. The use ofhydrogen peroxide is particularly preferred.

[0166] The composition according to the invention may also comprise anoxidation base. This oxidation base may be chosen from the oxidationbases conventionally used in oxidation dyeing, for examplepara-phenylenediamines, bis(phenyl)alkylenediamines, para-aminophenols,ortho-aminophenols and heterocyclic bases.

[0167] Among the para-phenylenediamines that may be mentioned, forexample, are para-phenylenediamine, para-tolylenediamine,2-chloro-para-phenylenediamine, 2,3-dimethyl-para-phenylenediamine,2,6-dimethyl-para-phenylene-diamine, 2,6-diethyl-para-phenylenediamine,2,5-dimethyl-para-phenylenediamine, N,N-dimethyl-para-phenylenediamine,N,N-diethyl-para-phenylenediamine, N,N-dipropyl-para-phenylenediamine,4-amino-N,N-diethyl-3-methylaniline,N,N-bis(β-hydroxyethyl)-para-phenylenediamine,4-N,N-bis(β-hydroxyethyl)amino-2-methylaniline,4-N,N-bis(β-hydroxyethyl)amino-2-chloroaniline,2-β-hydroxyethyl-para-phenylenediamine, 2-fluoro-para-phenylenediamine,2-isopropyl-para-phenylenediamine,N-(β-hydroxypropyl)-para-phenylenediamine,2-hydroxymethyl-para-phenylenediamine,N,N-dimethyl-3-methyl-para-phenylenediamine,N-ethyl-N-(β-hydroxyethyl)-para-phenylenediamine,N-(β,γ-dihydroxypropyl)-para-phenylenediamine,N-(4′-aminophenyl)-para-phenylenediamine,N-phenyl-para-phenylenediamine,2-β-hydroxyethyloxy-para-phenylenediamine,2-β-acetylamino-ethyloxy-para-phenylenediamine,N-(β-methoxyethyl)-para-phenylenediamine, 4-aminophenylpyrrolidine,2-thienyl-para-phenylenediamine, 2-β-hydroxyethylamino-5-aminotoluene,and the addition salts thereof with an acid.

[0168] Among the para-phenylenediamines mentioned above,para-phenylenediamine, para-tolylenediamine,2-isopropyl-para-phenylenediamine,2-β-hydroxyethyl-para-phenylene-diamine,2-β-hydroxyethyloxy-para-phenylenediamine,2,6-dimethyl-para-phenylenediamine, 2,6-diethyl-para-phenylenediamine,2,3-dimethyl-para-phenylenediamine,N,N-bis(β-hydroxyethyl)-para-phenylenediamine,2-chloro-para-phenylenediamine and2-β-acetylaminoethyloxy-para-phenylenediamine, and the addition saltsthereof with an acid, are particularly preferred.

[0169] Among the bis(phenyl)alkylenediamines that may be mentioned, forexample, areN,N′-bis(β-hydroxyethyl)-N,N′-bis(4′-aminophenyl)-1,3-diaminopropanol,N,N′-bis(β-hydroxyethyl)-N,N′-bis(4′-aminophenyl)ethylenediamine,N,N′-bis(4-aminophenyl)-tetramethylenediamine,N,N′-bis(β-hydroxyethyl)-N,N′-bis(4-aminophenyl)tetramethylenediamine,N,N′-bis(4-methylamino-phenyl)tetramethylenediamine,N,N′-bis(ethyl)-N,N′-bis(4′-amino-3′-methylphenyl)ethylenediamine and1,8-bis (2,5-diaminophenoxy)-3,6-dioxaoctane, and the addition saltsthereof with an acid.

[0170] Among the para-aminophenols that may be mentioned, for example,are para-aminophenol, 4-amino-3-methylphenol, 4-amino-3-fluorophenol,4-amino-3-hydroxymethylphenol, 4-amino-2-methylphenol,4-amino-2-hydroxymethylphenol, 4-amino-2-methoxymethylphenol,4-amino-2-aminomethylphenol,4-amino-2-(β-hydroxyethyl-aminomethyl)phenol and 4-amino-2-fluorophenol,and the addition salts thereof with an acid.

[0171] Among the ortho-aminophenols that may be mentioned, for example,are 2-aminophenol, 2-amino-5-methylphenol, 2-amino-6-methylphenol and5-acetamido-2-aminophenol, and the addition salts thereof with an acid.

[0172] Among the heterocyclic bases that may be mentioned, for example,are pyridine derivatives, pyrimidine derivatives and pyrazolederivatives.

[0173] Among the pyridine derivatives that may be mentioned are thecompounds described, for example, in patents GB 1 026 978 and GB 1 153196, such as 2,5-diaminopyridine,2-(4-methoxyphenyl)amino-3-aminopyridine, 2,3-diamino-6-methoxypyridine,2-(β-methoxyethyl)amino-3-amino-6-methoxypyridine and3,4-diaminopyridine, and the addition salts thereof with an acid.

[0174] Among the pyrimidine derivatives that can be mentioned are thecompounds described, for example, in patents DE 2 359 399; JP 88-169571; JP 05-163 124; EP 0 770 375 or patent application WO 96/15765, suchas 2,4,5,6-tetraaminopyrimidine, 4-hydroxy-2,5,6-triaminopyrimidine,2-hydroxy-4,5,6-triaminopyrimidine, 2,4-dihydroxy-5,6-diaminopyrimidineand 2,5,6-triaminopyrimidine, and pyrazolopyrimidine derivatives such asthose mentioned in patent application FR-A-2 750 048 and among whichmention may be made of pyrazolo[1,5-a]pyrimidine-3,7-diamine;2,5-dimethylpyrazolo[1,5-a]pyrimidine-3,7-diamine;pyrazolo[1,5-a]pyrimidine-3,5-diamine;2,7-dimethylpyrazolo[1,5-a]pyrimidine-3,5-diamine;3-aminopyrazolo[1,5-a]pyrimidin-7-ol;3-aminopyrazolo[1,5-a]pyrimidin-5-ol;2-(3-aminopyrazolo[1,5-a]pyrimidin-7-ylamino)ethanol,2-(7-aminopyrazolo[1,5-a]pyrimidin-3-ylamino)ethanol,2-[(3-aminopyrazolo[1,5-a]pyrimidin-7-yl) (2-hydroxyethyl)amino]ethanol,2-[(7-aminopyrazolo[1,5-a]pyrimidin-3-yl)(2-hydroxyethyl)amino]ethanol,5,6-dimethylpyrazolo[1,5-a]-pyrimidine-3,7-diamine,2,6-dimethylpyrazolo-[1,5-a]pyrimidine-3,7-diamine,2,5,N7,N7-tetramethyl-pyrazolo[1,5-a]pyrimidine-3,7-diamine and3-amino-5-methyl-7-imidazolylpropylaminopyrazolo[1,5-a]pyrimidine, andthe addition salts thereof with an acid and the tautomeric formsthereof, when a tautomeric equilibrium exists.

[0175] Among the pyrazole derivatives that may be mentioned are thecompounds described in patents DE 3 843 892 and DE 4 133 957 and patentapplications WO 94/08969, WO 94/08970, FR-A-2 733 749 and DE 195 43 988,such as 4,5-diamino-1-methylpyrazole,4,5-diamino-1-(β-hydroxyethyl)pyrazole, 3,4-diaminopyrazole,4,5-diamino-1-(4′-chlorobenzyl)pyrazole,4,5-diamino-1,3-dimethylpyrazole, 4,5-diamino-3-methyl-1-phenylpyrazole,4,5-diamino-1-methyl-3-phenylpyrazole,4-amino-1,3-dimethyl-5-hydrazinopyrazole,1-benzyl-4,5-diamino-3-methylpyrazole,4,5-diamino-3-tert-butyl-1-methylpyrazole,4,5-diamino-1-tert-butyl-3-methylpyrazole,4,5-diamino-1-(β-hydroxyethyl)-3-methylpyrazole,4,5-diamino-1-ethyl-3-methylpyrazole,4,5-diamino-1-ethyl-3-(4′-methoxyphenyl)pyrazole,4,5-diamino-1-ethyl-3-hydroxymethylpyrazole,4,5-diamino-3-hydroxymethyl-1-methylpyrazole,4,5-diamino-3-hydroxymethyl-1-isopropylpyrazole,4,5-diamino-3-methyl-1-isopropylpyrazole,4-amino-5-(2′-aminoethyl)amino-1,3-dimethylpyrazole,3,4,5-triaminopyrazole, 1-methyl-3,4,5-triaminopyrazole,3,5-diamino-1-methyl-4-methylaminopyrazole and3,5-diamino-4-(β-hydroxyethyl)amino-1-methylpyrazole, and the additionsalts thereof with an acid.

[0176] The composition according to the invention may also contain oneor more couplers conventionally used for dyeing keratin fibers. Amongthese couplers, mention may be made especially ofmeta-phenylenediamines, meta-aminophenols, meta-diphenols,naphthalene-based couplers and heterocyclic couplers.

[0177] Examples that may be mentioned include 2-methyl-5-aminophenol,5-N-(β-hydroxyethyl)amino-2-methylphenol,6-chloro-2-methyl-5-aminophenol, 3-aminophenol, 1,3-dihydroxybenzene,1,3-dihydroxy-2-methylbenzene, 4-chloro-1,3-dihydroxybenzene,2,4-diamino-1-(β-hydroxyethyloxy)benzene,2-amino-4-(β-hydroxyethylamino)-1-methoxybenzene, 1,3-diaminobenzene,1,3-bis(2,4-diaminophenoxy)propane, 3-ureidoaniline,3-ureido-1-dimethylaminobenzene, sesamol,1-β-hydroxyethylamino-3,4-methylenedioxybenzene, α-naphthol,2-methyl-1-naphthol, 6-hydroxyindole, 4-hydroxyindole,4-hydroxy-N-methylindole, 2-amino-3-hydroxypyridine,6-hydroxybenzomorpholine, 3,5-diamino-2,6-dimethoxypyridine,1-N-(β-hydroxyethyl)amino-3,4-methylenedioxybenzene and2,6-bis(β-hydroxy-ethylamino)toluene and the addition salts thereof withan acid.

[0178] In the composition of the present invention, the coupler(s)is(are) generally present in an amount ranging from 0.001% to 10% byweight approximately, and more preferably from 0.005% to 6% by weight,relative to the total weight of the dye composition. The oxidationbase(s) is(are) present in an amount preferably ranging from 0.001% to10% by weight approximately, and more preferably from 0.005% to 6% byweight, relative to the total weight of the dye composition.

[0179] In general, the addition salts with an acid that may be used inthe context of the dye compositions of the invention for the oxidationbases and couplers are chosen especially from the hydrochlorides,hydrobromides, sulfates, citrates, succinates, tartrates, lactates,tosylates, benzenesulfonates, phosphates and acetates.

[0180] The medium that is suitable for dyeing, also known as the dyesupport, generally consists of water or a mixture of water and at leastone organic solvent to dissolve the compounds which would not besufficiently soluble in water. As organic solvent, mention may be made,for example, of C₁-C₄ lower alkanols, such as ethanol and isopropanol;polyols and polyol ethers such as 2-butoxyethanol, propylene glycol,propylene glycol monomethyl ether, diethylene glycol monoethyl ether andmonomethyl ether, as well as aromatic alcohols such as benzyl alcohol orphenoxyethanol, and mixtures thereof.

[0181] The organic solvents may preferably be present in proportions ofbetween 1% and 40% by weight approximately relative to the total weightof the dye composition, and even more preferably between 5% and 30% byweight approximately.

[0182] The dye composition in accordance with the invention can alsocontain various adjuvants conventionally used in compositions for dyeingthe hair, such as anionic, cationic, nonionic, amphoteric orzwitterionic surfactants or mixtures thereof, anionic, cationic,nonionic, amphoteric or zwitterionic polymers or mixtures thereof,inorganic or organic thickeners, and in particular anionic, cationic,nonionic or amphoteric associative polymeric thickeners, antioxidants,penetration agents, sequestering agents, fragrances, buffers, dispersingagents, packaging agents such as, for example, silicones, which may ormay not be volatile or modified, film-forming agents, ceramides,preserving agents and opacifiers.

[0183] The above adjuvants are generally present in an amount for eachof them of between 0.01% and 20% by weight relative to the weight of thecomposition.

[0184] Needless to say, a person skilled in the art will take care toselect this or these optional additional compounds such that theadvantageous properties intrinsically associated with the oxidation dyecomposition in accordance with the invention are not, or are notsubstantially, adversely affected by the addition(s) envisaged.

[0185] The pH of the dye composition in accordance with the invention isgenerally between about 3 and 12 and preferably between about 5 and 11.It may be adjusted to the desired value using acidifying or basifyingagents usually used in the dyeing of keratin fibers, or alternativelyusing standard buffer systems.

[0186] Among the acidifying agents which may be mentioned, for example,are inorganic or organic acids such as hydrochloric acid,orthophosphoric acid, sulfuric acid, carboxylic acids such as aceticacid, tartaric acid, citric acid and lactic acid, and sulfonic acids.

[0187] Among the basifying agents which may be mentioned, for example,are aqueous ammonia, alkaline carbonates, alkanolamines such as mono-,di- and triethanolamine and derivatives thereof, sodium hydroxide,potassium hydroxide and the compounds of formula (III) below:

[0188] in which W is a propylene residue which is unsubstituted orsubstituted with a hydroxyl group or a C₁-C₄ alkyl radical; R₆, R₇, R₈and R₉, which may be identical or different, represent a hydrogen atom,a C₁-C₄ alkyl radical or a C₁-C₄ hydroxyalkyl radical.

[0189] The dye composition according to the invention may be in variousforms, such as in the form of liquids, creams or gels, or in any otherform that is suitable for dyeing keratin fibers, and especially humanhair.

[0190] A subject of the invention is also a process of direct dyeing,which comprises the application of a dye composition comprising a dye offormula (I) as defined above to keratin fibers. After a leave-in time,the keratin fibers are rinsed, revealing colored fibers.

[0191] The dye composition comprising the cationic azo dye of formula(I) may be applied to the fibers in the presence of an oxidizing agent,which causes bleaching of the fiber (lightening direct dyeing). Thisoxidizing agent may be added to the composition comprising the cationicazo dye at the time of use or directly onto the keratin fiber.

[0192] A subject of the invention is also a process of oxidation dyeing,which comprises the application to the fibers of a dye compositioncomprising a dye of formula (I), at least one oxidation base andoptionally at least one coupler, in the presence of an oxidizing agent.

[0193] The oxidation base, the coupler and the oxidizing agent are asdefined above.

[0194] The color may be revealed at acidic, neutral or alkaline pH andthe oxidizing agent may be added to the composition of the inventionjust at the time of use, or it may be introduced using an oxidizingcomposition containing it, applied to the fibers simultaneously with orsequentially to the dye composition.

[0195] In the case of oxidation dyeing or lightening direct dyeing, thedye composition is mixed, preferably at the time of use, with acomposition containing, in a medium that is suitable for dyeing, atleast one oxidizing agent, this oxidizing agent being present in anamount that is sufficient to develop a coloration. The mixture obtainedis then applied to the keratin fibers. After a leave-in time of 3 to 50minutes approximately and preferably 5 to 30 minutes approximately, thekeratin fibers are rinsed, washed with shampoo, rinsed again and thendried.

[0196] The oxidizing composition may also contain various adjuvantsconventionally used in compositions for dyeing the hair, and as definedabove.

[0197] The pH of the oxidizing composition containing the oxidizingagent is such that, after mixing with the dye composition, the pH of theresulting composition applied to the keratin fibers preferably rangesfrom 3 to 12 approximately, and even more preferably between 5 and 11.It may be adjusted to the desired value by means of acidifying orbasifying agents usually used in the dyeing of keratin fibers, and asdefined above.

[0198] The composition that is finally applied to the keratin fibers maybe in various forms, such as in the form of liquids, creams or gels orin any other form that is suitable for dyeing keratin fibers, andespecially human hair.

[0199] Another subject of the invention is a multi-compartment device ordyeing “kit”, in which a first compartment contains the dye compositionof the invention and a second compartment contains the oxidizingcomposition. This device may be equipped with a means for applying thedesired mixture to the hair, such as the devices described in patentFR-2 586 913 in the name of the Applicant.

[0200] Finally, a subject of the invention is also novel dicationicdiazo dyes of formula (I) as defined above, for which,

[0201] when p=1,

[0202] W₁ to W₅ and L have the same meanings as defined above,

[0203] when p=0,

[0204] W₃ represents an oxygen atom and the other groups of formula (I)have the same meanings as defined above, or

[0205] W₃ represents a radical —NR₁₄— and L represents an aryl orheteroaryl radical optionally substituted with one or more radicalschosen from hydroxyl, C₁-C₂ alkoxy, C₂-C₄ (poly)hydroxyalkoxy, amino,C₁-C₂ (di)alkylamino, carboxyl and sulfonic radicals, or a halogen atomsuch as chlorine, fluorine or bromine.

[0206] Synthesis of the Compounds of the Invention

[0207] The methods for obtaining said compounds are based on reactionsthat are already well known in the literature and disclosed, forexample, in the following documents: U.S. Pat. No. 3,291,788, GB-1 186753, U.S. Pat. No. 3,271,383, EP-0 757 083 and U.S. Pat. No. 5,708,151.

[0208] A first synthetic principle consists in starting with a 5- or6-membered amino heterocycle, such as 3-aminotriazole, 2-aminothiazole,3-aminothiadiazole, 2-aminopyridine or 2-aminopyridazine, which isreacted with sodium nitrite in a polar acidic protic solvent, such asacetic acid or hydrochloric acid, at a temperature generally of between−10° C. and 50° C., in order to generate the corresponding diazoniumsalt. This salt then reacts with an aromatic derivative of formula (A)or (B) described below, in which:

[0209] W₃, W₅, X₁, X₂ and L have the meanings described above accordingto the invention. These aromatic derivatives are obtained by applyingthe conventional SNAr (aromatic nucleophilic substitution), SN1(nucleophilic substitution 1) and SN2 (nucleophilic substitution 2)reactions of the literature.

[0210] The resulting condensation product then reacts with an alkylatingagent such as a dialkyl sulfate or an alkyl halide in a polar solventand at a temperature of between 0° C. and 150° C. and preferably between20° C. and 100° C. The 5- or 6-membered heterocyclic part is thusquaternized and the azo compound obtained is cationic.

[0211] With a 5-membered heterocycle:

[0212] With a 6-membered heterocycle:

[0213] A second synthetic principle consists in reacting a heterocyclicazo compound 1 quaternized on one of the nitrogen atoms of theheterocycle as a 4-methoxyphenylazo series, with an aniline or phenolderivative or a heteroaromatic amine 2 in a protic solvent at atemperature of between 25° C. and 150° C. In particular, the quaternaryheterocycle may be a triazolium, thiazolium, thiadiazolium or oxazolium.The same synthetic principle may be applied in the 6-memberedheterocyclic series, such as pyridinium or pyridazinium, giving thecompounds of formula 4′ from the azo compound 1′.

[0214] The cationic azo derivative 3 then reacts with a di-electrophilesuch as an alkyl dihalide, an alkylaryl dihalide, a triazine dihalide, apyrimidine dihalide or a diacyl chloride, to give the cationic azocompound 4.

[0215] In the particular case in which W₅ represents an amino, thederivative 3 may react with an aryl dihalide in the presence of atransition metal such as palladium (II) or copper (I) to give compound 4according to the Buchwald or Meerwein reaction, which are well known inthe literature.

[0216] A third synthetic principle consists in reacting a heterocyclicazo compound 1 quaternized on one of the nitrogen atoms of theheterocycle as a 4-methoxyphenylazo series, with a diamino derivative ofthe type W₃-L-W₃ (in which W₃═NH₂) in a protic solvent at a temperatureof between 25° C. and 150° C. In particular, the quaternary heterocyclemay be a triazolium, thiazolium, thiadiazolium or oxazolium. Thecompounds of formula 5 are thus obtained. The same synthetic principlemay be applied in the 6-membered heterocyclic series, such as pyridiniumor pyridazinium, to give the compounds of formula 5′ from the azocompound 1′.

[0217] In the formulae of the synthetic scheme, Me denotes a CH₃radical.

EXAMPLE OF SYNTHESIS

[0218] Compound b having the formula below in accordance with theinvention is obtained according to process 1 or process 2 below (inwhich Me denotes a CH₃ radical)

[0219] Process 1:

[0220] Process 2:

[0221] The diazonium salt of 3-aminotriazole (0.5 mmol) is preparedaccording to the protocol described in patent GB-1 186 753 or U.S. Pat.No. 3,291,788. A solution of 1 mmol of bis(N-phenylamino)propane in 10ml of 15% sulfuric acid is added at 0° C. to the diazonium salt preparedabove with vigorous stirring. After disappearance of the reagents, thereaction medium is poured onto ice and the precipitate is filtered offby suction, washed with water and then dried to constant weight to givecompound d.

[0222] Compound d (0.2 mmol) is then dissolved in 30 ml ofdimethylformamide and 1 mmol of dimethyl sulfate is added to thissolution. The reaction medium is then brought to 90-100° C. withstirring. After 6 hours, the reaction medium is poured into 100 ml ofwater at room temperature and the solution is concentrated to dryness toconstant weight to give 0.04 mmol of the desired compound b, the λ_(max)of which is 520 nm in a methanolic 1% acetic acid solution.

[0223] The dye obtained dyed hair in an iridescent red shade.

1-41. (canceled)
 42. A composition for dyeing human keratin fibers,comprising at least one dicationic diazo dye of formula (I):[W₁—N═N—W₂—W₃—(W₄—W₅)_(p)-]₂-L   Formula (I) wherein: p=0 or 1, W₁ ischosen from heteroaromatic radicals of formulae (II) and (III):

W₂ is chosen from carbon-based, pyridine-based and pyridazine-basedaromatic groups of formula (IV):

W₃ and W₅, which may be identical or different, are chosen from —NR₁₄—radicals, and oxygen and nitrogen atoms, W₄ is chosen from saturated andunsaturated, linear and branched C₁-C₁₆ hydrocarbon-based chains, whichcan form at least one 3- to 6-membered carbon-based ring, wherein atleast one carbon atom of the carbon-based chain may optionally bereplaced with an entity chosen from oxygen, nitrogen and sulfur atomsand from SO₂ groups, and further wherein the carbon atoms may optionallybe substituted, independently of each other, with at least one halogenatom, provided that W₄ does not comprise a peroxide bond or diazo ornitroso radicals; piperazine rings; and groups of formula (V):

wherein in formulae (II), (III), (IV) and (V): X₁ is chosen fromnitrogen atoms and CR₅ radicals, X₂ is chosen from nitrogen atoms andCR₆ radicals, X₃ is chosen from nitrogen atoms and CR₁₇ radicals, X₄ ischosen from nitrogen atoms and CR₁₈ radicals, Z₁ is chosen from oxygenand sulfur atoms, and NR₈ radicals, Z₂ is chosen from nitrogen atoms andCR₉ atoms, with the proviso that when Z₁is chosen from NR₈ radicals, Z₂is not chosen from CR₉ radicals, such that formula (II) is not animidazolium ring, Z₃ is chosen from nitrogen atoms and CR₁₂ radicals, Z₄is chosen from nitrogen atoms and CR₁₃ radicals, the bond a of the5-membered cationic ring of formula (II) is linked to the azo group offormula (I), the bond b of the 6-membered cationic ring of formula (III)is linked to the azo group of formula (I), wherein when p=0, then L ischosen from linear and branched, saturated C₁-C₁₆ hydrocarbon-basedchains, which can form at least one 3- to 6-membered carbon-based ring,wherein at least one carbon atom of the carbon-based chain is optionallyreplaced with an entity chosen from oxygen, nitrogen and sulfur atomsand from SO₂ groups, and further wherein the carbon atoms of the chainare optionally substituted, independently of each other, with at leastone halogen atom; with the proviso that L does not comprise a peroxidebond or diazo or nitroso radicals, wherein when p=1, then L is chosenfrom saturated and unsaturated, linear and branched C₁-C₁₆hydrocarbon-based chains, which can form at least one 3- to 6-memberedcarbon-based ring, wherein at least one carbon atom of the carbon-basedchain is optionally replaced with an entity chosen from oxygen, nitrogenand sulfur atoms and from SO₂ groups; with the proviso that L does notcomprise a peroxide bond or diazo or nitroso radicals, R₃, R₄, R₅, R₆,R₇, R₉, R₁₀, R₁₁, R₁₂, R₁₃, R₁₄, R₁₅, R₁₆, R₁₇ and R₁₈, which may beidentical or different, are chosen from hydrogen atoms, saturated andunsaturated, linear and branched C₁-C₁₆ hydrocarbon-based chains, whichcan form at least one 3- to 6-membered carbon-based ring, wherein atleast one carbon atom of the carbon-based chain is optionally replacedwith an entity chosen from oxygen, nitrogen and sulfur atoms, and fromSO₂ groups, and the carbon atoms of the chain are optionallysubstituted, independently of each other, with at least one halogenatom; and with the proviso that R₃, R₄, R₅, R₆, R₇, R₉, R₁₀, R₁₁, R₁₂,R₁₃, R₁₄, R₁₅, R₁₆, R₁₇ and R₁₈ do not comprise a peroxide bond or diazoor nitroso radicals, R₃ with R₄, R₇ with R₉, R₁₀ with R₁₁, R₁₂ with R₁₃and R₁₅ with R₁₆ may optionally form a carbon-based aromatic ring, R₁,R₂ and R₈ are chosen from linear and branched C₁-C₈ alkyl radicalsoptionally substituted with at least one radical chosen from hydroxyl,C₁-C₂ alkoxy, C₂-C₄ (poly)hydroxyalkoxy, amino, C₁-C₂ (di)alkylamino,carboxyl and sulfonic radicals; and optionally substituted phenylradicals, and X is chosen from organic and mineral anions.
 43. Thecomposition according to claim 42, wherein the human keratin fibers arehair.
 44. The composition according to claim 42, wherein R₃, R₄, R₅, R₆,R₁₀, R₁₁, R₁₂, R₁₃, R₁₅, R₁₆, R₁₇ and R₁₈, which may be identical ordifferent, are chosen from hydrogen atoms; linear and branched C₁-C₄alkyl radicals, optionally substituted with at least one radical chosenfrom hydroxyl, C₁-C₂ alkoxy, C₂-C₄ (poly)hydroxyalkoxy, amino, C₁-C₂(di)alkylamino, carboxyl and sulfonic radicals; phenyl radicalsoptionally substituted with at least one radical chosen from hydroxyl,C₁-C₂ alkoxy, C₂-C₄ (poly)hydroxyalkoxy, amino, C₁-C₂ (di)alkylamino,carboxyl and sulfonic radicals, and halogen atoms; carboxyl radicals;sulfonylamino radicals; sulfonic radicals; C₁-C₂ alkoxy radicals; C₂-C₄(poly)hydroxyalkoxy radicals; amino radicals; C₁-C₂ (di)alkylaminoradicals; and C₂-C₄ (poly)hydroxyalkylamino radicals.
 45. Thecomposition according to claim 44, wherein R₃, R₄, R₅, R₆, R₁₀, R₁₁,R₁₂, R₁₃, R₁₅, R₁₆, R₁₇ and R₁₈ are chosen from hydrogen atoms; C₁-C₄alkyl radicals optionally substituted with at least one radical chosenfrom hydroxyl, amino and C₁-C₂ (di)alkylamino radicals; carboxylradicals; C₁-C₂ alkoxy radicals; amino radicals; C₁-C₂ (di)alkylaminoradicals; and C₂-C₄ (poly)hydroxyalkylamino radicals.
 46. Thecomposition according to claim 45, wherein R₃, R₄, R₅, R₆, R₁₀, R₁₁,R₁₂, R₁₃, R₁₅, R₁₆, R₁₇ and R₁₈ are chosen from hydrogen atoms; methyl,phenyl and 2-hydroxymethyl radicals; carboxyl, methoxy, ethoxy and2-hydroxyethyloxy radicals; and amino, methylamino, dimethylamino and2-hydroxyethylamino radicals.
 47. The composition according to claim 42,wherein R₇ and R₉, which may be identical or different, are chosen fromhydrogen atoms; linear and branched C₁-C₄ alkyl radicals optionallysubstituted with at least one radical chosen from hydroxyl, C₁-C₂alkoxy, C₂-C₄ (poly)hydroxyalkoxy, amino, C₁-C₂ (di)alkylamino, carboxyland sulfonic radicals; optionally substituted phenyl radicals; carboxylradicals; and sulfonylamino radicals.
 48. The composition according toclaim 47, wherein R₇ and R₉ are chosen from hydrogen atoms; phenylradicals and C₁-C₄ alkyl radicals optionally substituted with at leastone radical chosen from hydroxyl, amino, C₁-C₂ (di)alkylamino andcarboxyl radicals.
 49. The composition according to claim 48, wherein R₇and R₉ are chosen from hydrogen atoms; methyl, phenyl and2-hydroxymethyl radicals; and carboxyl radicals.
 50. The compositionaccording to claim 42, wherein R₁₄ is chosen from hydrogen atoms; linearand branched C₁-C₆ alkyl radicals, optionally substituted with at leastone radical chosen from hydroxyl, C₁-C₂ alkoxy, C₂-C₄(poly)hydroxyalkoxy, amino, C₁-C₂ (di)alkylamino, carboxyl and sulfonicradicals; and optionally substituted phenyl radicals.
 51. Thecomposition according to claim 50, wherein R₁₄ is chosen from hydrogenatoms; linear and branched C₁-C₄ alkyl radicals, optionally substitutedwith at least one radical chosen from hydroxyl, C₁-C₂ alkoxy, amino andC₁-C₂ (di)alkylamino radicals.
 52. The composition according to claim51, wherein R₁₄ is chosen from hydrogen atoms; methyl, ethyl,2-hydroxyethyl, 2-aminoethyl, 2-methoxyethyl, 1-carboxymethyl,2-carboxyethyl and 2-sulfonylethyl radicals.
 53. The compositionaccording to claim 52, wherein R₁₄ is chosen from hydrogen atoms;methyl, ethyl, 2-hydroxyethyl and 2-aminoethyl radicals.
 54. Thecomposition according to claim 42, wherein R₁, R₂ and R₈ are chosen fromC₁-C₄ alkyl radicals optionally substituted with at least one radicalchosen from hydroxyl, C₁-C₂ alkoxy, amino, C₁-C₂ (di)alkylamino,carboxyl and sulfonic radicals.
 55. The composition according to claim54, wherein R₁, and R₂ and R₈ are chosen from methyl, ethyl,2-hydroxyethyl, 1-carboxymethyl, 2-carboxyethyl and 2-sulfonylethylradicals.
 56. The composition according to claim 42, wherein W₁ ischosen from triazolium, thiazolium and pyridinium cationic groups offormulae (II) and (III), wherein R₁ and R₂ are chosen from linear andbranched C₁-C₈ alkyl radicals optionally substituted with at least oneradical chosen from hydroxyl, C₁-C₂ alkoxy, C₂-C₄ (poly)hydroxyalkoxy,amino, C₁-C₂ (di)alkylamino, carboxyl and sulfonic radicals; andoptionally substituted phenyl radicals, R₇ is chosen from hydrogenatoms; linear and branched C₁-C₄ alkyl radicals optionally substitutedwith at least one radical chosen from hydroxyl, C₁-C₂ alkoxy, C₂-C₄(poly)hydroxyalkoxy, amino, C₁-C₂ (di)alkylamino, carboxyl and sulfonicradicals; optionally substituted phenyl radicals; carboxyl radicals; andsulfonylamino radicals; and R₁₀, R₁₁, R₁₂ and R₁₃, which may beidentical or different, are chosen from hydrogen atoms; linear andbranched C₁-C₄ alkyl radicals, optionally substituted with at least oneradical chosen from hydroxyl, C₁-C₂ alkoxy, C₂-C₄ (poly)hydroxyalkoxy,amino, C₁-C₂ (di)alkylamino, carboxyl and sulfonic radicals; phenylradicals optionally substituted with at least one radical chosen fromhydroxyl, C₁-C₂ alkoxy, C₂-C₄ (poly)hydroxyalkoxy, amino, C₁-C₂(di)alkylamino, carboxyl and sulfonic radicals, and halogen atoms;carboxyl radicals; sulfonylamino radicals; sulfonic radicals; C₁-C₂alkoxy radicals; C₂-C₄ (poly)hydroxyalkoxy radicals; amino radicals;C₁-C₂ (di)alkylamino radicals; and C₂-C₄ (poly)hydroxyalkylaminoradicals.
 57. The composition according to claim 42, wherein W₂ ischosen from phenyl and pyridyl groups of formula (IV), wherein R₃, R₄,R₅ and R₆, which may be identical or different, are chosen from hydrogenatoms; linear and branched C₁-C₄ alkyl radicals, optionally substitutedwith at least one radical chosen from hydroxyl, C₁-C₂ alkoxy, C₂-C₄(poly)hydroxyalkoxy, amino, C₁-C₂ (di)alkylamino, carboxyl and sulfonicradicals; phenyl radicals optionally substituted with at least oneradical chosen from hydroxyl, C₁-C₂ alkoxy, C₂-C₄ (poly)hydroxyalkoxy,amino, C₁-C₂ (di)alkylamino, carboxyl and sulfonic radicals, and halogenatoms; carboxyl radicals; sulfonylamino radicals; sulfonic radicals;C₁-C₂ alkoxy radicals; C₂-C₄ (poly)hydroxyalkoxy radicals; aminoradicals; C₁-C₂ (di)alkylamino radicals; and C₂-C₄(poly)hydroxyalkylamino radicals.
 58. The composition according to claim42, wherein W₃ and W₅, which may be identical or different, are chosenfrom —NR₁₄— groups, wherein R₁₄ is chosen from hydrogen atoms; linearand branched C₁-C₆ alkyl radicals, optionally substituted with at leastone radical chosen from hydroxyl, C₁-C₂ alkoxy, C₂-C₄(poly)hydroxyalkoxy, amino, C₁-C₂ (di)alkylamino, carboxyl and sulfonicradicals; and optionally substituted phenyl radicals.
 59. Thecomposition according to claim 42, wherein W₄ is chosen from linear andbranched C₂-C₆ alkyl radicals optionally substituted with at least oneradical chosen from hydroxyl, C₁-C₂ alkoxy, C₂-C₄ (poly)hydroxyalkoxy,amino, C₁-C₂ (di)alkylamino, carboxyl and sulfonic radicals; phenylradicals optionally substituted with at least one radical chosen fromhydroxyl, C₁-C₂ alkoxy, C₂-C₄ (poly)hydroxyalkoxy, amino, C₁-C₂(di)alkylamino, carboxyl and sulfonic radicals, and halogen atoms;naphthyl radicals optionally substituted with at least one radicalchosen from hydroxyl, C₁-C₂ alkoxy, C₂-C₄ (poly)hydroxyalkoxy, amino,C₁-C₂ (di)alkylamino, carboxyl and sulfonic radicals; halogen atoms; andpiperazine radicals formed with the two radicals W₃ and W₅.
 60. Thecomposition according to claim 59, wherein W₄ is chosen from linear andbranched C₂-C₄ alkyl radicals optionally substituted with at least onehydroxyl radical; phenyl radicals optionally substituted with at leastone radical chosen from hydroxyl, C₁-C₂ alkoxy, C₂-C₄(poly)hydroxyalkoxy, amino, C₁-C₂ (di)alkylamino, carboxyl and sulfonicradicals; naphthyl radicals optionally substituted with at least oneradical chosen from hydroxyl, C₁-C₂ alkoxy, C₂-C₄ (poly)hydroxyalkoxy,amino, C₁-C₂ (di)alkylamino, carboxyl and sulfonic radicals; andpiperazine radicals formed with the two radicals W₃ and W₅.
 61. Thecomposition according to claim 61, wherein W₄ is chosen from ethyl,propyl, butyl and 2-hydroxypropyl radicals; phenyl radicals; naphthylradicals; and piperazine rings formed with the two radicals W₃ and W₅.62. The composition according to claim 42, wherein L is an entity chosenfrom —CO—; —CO—CH₂—CH₂—CO—; —CO—CO—; benzo-1,4-dicarbonyl; ethyl;1,4-phenyl; triazine; and pyrimidine.
 63. The composition according toclaim 62, wherein L is chosen from ethyl and triazine groups.
 64. Thecomposition according to claim 42, wherein the dicationic diazo dyes offormula (I) are chosen from those of the following formulae:


65. The composition according to claim 64, wherein the dicationic diazodyes of formula (I) are chosen from those comprising a triazolium ring.66. The composition according to claim 42, wherein the at least onedicationic diazo dye of formula (I) is present in an amount ranging from0.001% to 5% by weight, relative to the total weight of the composition.67. The composition according to claim 66, wherein the at least onedicationic diazo dye of formula (I) is present in an amount ranging from0.05% to 2% by weight, relative to the total weight of the composition.68. The composition according to claim 42 further comprising at leastone oxidation base.
 69. The composition according to claim 68, whereinthe at least one oxidation base is chosen from para-phenylenediamines,bis(phenyl)alkylenediamines, para-aminophenols, ortho-aminophenols,heterocyclic bases, and the acid addition salts thereof.
 70. Thecomposition according to claim 68, wherein the at least one oxidationbase is present in an amount ranging from 0.001% to 10% by weight,relative to the total weight of the composition.
 71. The compositionaccording to claim 70, wherein the at least one oxidation base ispresent in an amount ranging from 0.005% to 6% by weight, relative tothe total weight of the composition.
 72. The composition according toclaim 42, further comprising at least one coupler.
 73. The compositionaccording to claim 72, wherein the at least one coupler is chosen frommeta-phenylenediamines, meta-aminophenols, meta-diphenols,naphthalene-based couplers, heterocyclic couplers, and the acid additionsalts thereof.
 74. The composition according to claim 42 furthercomprising at least one additional direct dye, chosen from neutral,acidic and cationic nitrobenzene direct dyes; neutral, acidic andcationic azo direct dyes; quinone direct dyes; azine direct dyes;methine direct dyes; triarylmethane direct dyes; indoamine direct dyes;and natural direct dyes, with the proviso that the at least oneadditional direct dye is other than those of formula (I).
 75. Thecomposition according to claim 74, wherein the at least one quinonedirect dye is chosen from neutral, acidic and cationic anthraquinonedirect dyes.
 76. The composition according to claim 42 furthercomprising at least one oxidizing agent.
 77. The composition accordingto claim 76, wherein the at least one oxidizing agent is hydrogenperoxide.
 78. A process for dyeing human keratin fibers, comprisingapplying to the fibers a composition comprising at least one dicationicdiazo dye of formula (I): [W₁—N═N—W₂—W₃—(W₄—W₅)_(p)-]₂-L   Formula (I)wherein: p=0 or 1, W₁ is chosen from heteroaromatic radicals of formulae(II) and (III):

W₂ is chosen from carbon-based, pyridine-based and pyridazine-basedaromatic groups of formula (IV):

W₃ and W₅, which may be identical or different, are chosen from —NR₁₄—radicals, and oxygen and nitrogen atoms, W₄ is chosen from saturated andunsaturated, linear and branched C₁-C₁₆ hydrocarbon-based chains, whichcan form at least one 3- to 6-membered carbon-based ring, wherein atleast one carbon atom of the carbon-based chain may optionally bereplaced with an entity chosen from oxygen, nitrogen and sulfur atoms,and from SO₂ groups, and further wherein the carbon atoms may optionallybe substituted, independently of each other, with at least one halogenatom, provided that W₄ does not comprise a peroxide bond or diazo ornitroso radicals; piperazine rings; and groups of formula (V):

wherein in formulae (II), (III), (IV) and (V): X₁ is chosen fromnitrogen atoms and CR₅ radicals, X₂ is chosen from nitrogen atoms andCR₆ radicals, X₃ is chosen from nitrogen atoms and CR₁₇ radicals, X₄ ischosen from nitrogen atoms and CR₁₈ radicals, Z₁ is chosen from oxygenand sulfur atoms, and NR₈ radicals, Z₂ is chosen from nitrogen atoms andCR₉ atoms, with the proviso that when Z₁ is chosen from NR₈ radicals,then Z₂ is not chosen from CR₉ radicals, such that formula (II) is notan imidazolium ring, Z₃ is chosen from nitrogen atoms and CR₁₂ radicals,Z₄ is chosen from nitrogen atoms and CR₁₃ radicals, the bond a of the5-membered cationic ring of formula (II) is linked to the azo group offormula (I), the bond b of the 6-membered cationic ring of formula (III)is linked to the azo group of formula (I), wherein when p=0, then L ischosen from linear and branched, saturated C₁-C₁₆ hydrocarbon-basedchains, which can form at least one 3- to 6-membered carbon-based ring,wherein at least one carbon atom of the carbon-based chain is optionallyreplaced with an entity chosen from oxygen, nitrogen and sulfur atomsand from SO₂ groups, and further wherein the carbon atoms of the chainare optionally substituted, independently of each other, with at leastone halogen atom; with the proviso that L does not comprise a peroxidebond or diazo or nitroso radicals, wherein when p=1, then L is chosenfrom saturated and unsaturated, linear and branched C₁-C₁₆hydrocarbon-based chains, which can form at least one 3- to 6-memberedcarbon-based ring, wherein at least one carbon atom of the carbon-basedchain is optionally replaced with an entity chosen from oxygen, nitrogenand sulfur atoms and from SO₂ groups; with the proviso that L does notcomprise a peroxide bond or diazo or nitroso radicals, R₃, R₄, R₅, R₆,R₇, R₉, R₁₀, R₁₁, R₁₂, R₁₃, R₁₄, R₁₅, R₁₆, R₁₇ and R₁₈, which may beidentical or different, are chosen from hydrogen atoms, saturated andunsaturated, linear and branched C₁-C₁₆ hydrocarbon-based chains, whichcan form at least one 3- to 6-membered carbon-based ring, wherein atleast one carbon atom of the carbon-based chain is optionally replacedwith an entity chosen from oxygen, nitrogen and sulfur atoms, and fromSO₂ groups, and the carbon atoms of the chain are optionallysubstituted, independently of each other, with at least one halogenatom; and with the proviso that R₃, R₄, R₅, R₆, R₇, R₉, R₁₀, R₁₁, R₁₂,R₁₃, R₁₄, R₁₅, R₁₆, R₁₇ and R₁₈ do not comprise a peroxide bond or diazoor nitroso radicals, R₃ with R₄, R₇ with R₉, R₁₀ with R₁₁, R₁₂ with R₁₃and R₁₅ with R₁₆ can optionally form a carbon-based aromatic ring, R₁,R₂ and R₈ are chosen from linear and branched C₁-C₈ alkyl radicalsoptionally substituted with at least one radical chosen from hydroxyl,C₁-C₂ alkoxy, C₂-C₄ (poly)hydroxyalkoxy, amino, C₁-C₂ (di)alkylamino,carboxyl and sulfonic radicals; and optionally substituted phenylradicals, and X is chosen from organic and mineral anions.
 79. Theprocess according to claim 78, wherein the human keratin fibers arehair.
 80. The process according to claim 78, wherein the dye compositioncomprises at least one oxidizing agent.
 81. The process according toclaim 80, wherein the at least one oxidizing agent is mixed with the dyecomposition at the time of use.
 82. The process according to claim 80,wherein the at least one oxidizing agent is applied to the fibers in theform of an oxidizing composition either simultaneously with, orsequentially to, the application of the dye composition.
 83. A processfor the oxidation dyeing of human keratin fibers, comprising applying tothe fibers, at least one dye composition in the presence of at least oneoxidizing agent, wherein the at least one dye composition comprises atleast one oxidation base, optionally at least one coupler, and at leastone dicationic diazo dye of formula (I): [W₁—N═N—W₂—W₃—(W₄—W₅)_(p)-]₂-L  Formula (I) wherein: p=0 or 1, W₁ is chosen from heteroaromaticradicals of formulae (II) and (III):

W₂ is chosen from carbon-based, pyridine-based and pyridazine-basedaromatic groups of formula (IV):

W₃ and W₅, which may be identical or different, are chosen from —NR₁₄—radicals, and oxygen and nitrogen atoms, W₄ is chosen from saturated andunsaturated, linear and branched C₁-C₁₆ hydrocarbon-based chains, whichcan form at least one 3- to 6-membered carbon-based ring, wherein atleast one carbon atom of the carbon-based chain may optionally bereplaced with an entity chosen from oxygen, nitrogen and sulfur atoms,and from SO₂ groups, and further wherein the carbon atoms may optionallybe substituted, independently of each other, with at least one halogenatom, provided that W₄ does not comprise a peroxide bond or diazo ornitroso radicals; piperazine rings; and groups of formula (V):

wherein in formulae (II), (III), (IV) and (V): X₁ is chosen fromnitrogen atoms and CR₅ radicals, X₂ is chosen from nitrogen atoms andCR₆ radicals, X₃ is chosen from nitrogen atoms and CR₁₇ radicals, X₄ ischosen from nitrogen atoms and CR₁₈ radicals, Z₁ is chosen from oxygenand sulfur atoms, and NR₈ radicals, Z₂ is chosen from nitrogen atoms andCR₉ atoms, with the proviso that when Z₁ is chosen from NR₈ radicals,then Z₂ is not chosen from CR₉ radicals, such that formula (II) is notan imidazolium ring, Z₃ is chosen from nitrogen atoms and CR₁₂ radicals,Z₄ is chosen from nitrogen atoms and CR₁₃ radicals, the bond a of the5-membered cationic ring of formula (II) is linked to the azo group offormula (I), the bond b of the 6-membered cationic ring of formula (III)is linked to the azo group of formula (I), wherein when p=0, then L ischosen from linear and branched, saturated C₁-C₁₆ hydrocarbon-basedchains, which can form at least one 3- to 6-membered carbon-based ring,wherein at least one carbon atom of the carbon-based chain is optionallyreplaced with an entity chosen from oxygen, nitrogen and sulfur atoms,and from SO₂ groups, and further wherein the carbon atoms of the chainare optionally substituted, independently of each other, with at leastone halogen atom; with the proviso that L does not comprise a peroxidebond or diazo or nitroso radicals, wherein when p=1, then L is chosenfrom saturated and unsaturated, linear and branched C₁-C₁₆hydrocarbon-based chains, which can form at least one 3- to 6-memberedcarbon-based ring, wherein at least one carbon atom of the carbon-basedchain is optionally replaced with an entity chosen from oxygen, nitrogenand sulfur atoms, and SO₂ groups; with the proviso that L does notcomprise a peroxide bond or diazo or nitroso radicals, R₃, R₄, R₅, R₆,R₇, R₉, R₁₀, R₁₁, R₁₂, R₁₃, R₁₄, R₁₅, R₁₆, R₁₇ and R₁₈, which may beidentical or different, are chosen from hydrogen atoms, saturated andunsaturated, linear and branched C₁-C₁₆ hydrocarbon-based chains, whichcan form at least one 3- to 6-membered carbon-based ring, wherein atleast one carbon atom of the carbon-based chain is optionally replacedwith an entity chosen from oxygen, nitrogen and sulfur atoms, and fromSO₂ groups, and the carbon atoms of the chain are optionallysubstituted, independently of each other, with at least one halogenatom; and with the proviso that R₃, R₄, R₅, R₆, R₇, R₉, R₁₀, R₁₁, R₁₂,R₁₃, R₁₄, R₁₅, R₁₆, R₁₇ and R₁₈ do not comprise a peroxide bond or diazoor nitroso radicals, R₃ with R₄, R₇ with R₉, R₁₀ with R₁₁, R₁₂ with R₁₃and R₁₅ with R₁₆ can optionally form a carbon-based aromatic ring, R₁,R₂ and R₈ are chosen from linear and branched C₁-C₈ alkyl radicalsoptionally substituted with at least one radical chosen from hydroxyl,C₁-C₂ alkoxy, C₂-C₄ (poly)hydroxyalkoxy, amino, C₁-C₂ (di)alkylamino,carboxyl and sulfonic radicals; and optionally substituted phenylradicals, and X is chosen from organic and mineral anions.
 84. Theprocess according to claim 83, wherein the human keratin fibers arehair.
 85. The process according to claim 83, wherein the at least oneoxidizing agent is mixed with the dye composition at the time of use.86. The process according to claim 83, wherein the at least oneoxidizing agent is applied to the fibers in the form of an oxidizingcomposition either simultaneously with, or sequentially to, theapplication of the dye composition.
 87. A multi-compartment kit, whereinat least one first compartment comprises a composition comprising atleast one dicationic diazo dye of formula (I):[W₁—N═N—W₂—W₃—(W₄—W₅)_(p)-]₂-L   Formula (I) wherein: p=0 or 1, W₁ ischosen from heteroaromatic radicals of formulae (II) and (III):

W₂ is chosen from carbon-based, pyridine-based and pyridazine-basedaromatic groups of formula (IV):

W₃ and W₅, which may be identical or different, are chosen from —NR₁₄—radicals, and oxygen and nitrogen atoms, W₄ is chosen from saturated andunsaturated, linear and branched C₁-C₁₆ hydrocarbon-based chains, whichcan form at least one 3- to 6-membered carbon-based ring, wherein atleast one carbon atom of the carbon-based chain may optionally bereplaced with an entity chosen from oxygen, nitrogen and sulfur atomsand from SO₂ groups, and further wherein the carbon atoms may optionallybe substituted, independently of each other, with at least one halogenatom, provided that W₄ does not comprise a peroxide bond or diazo ornitroso radicals; piperazine rings; and groups of formula (V):

wherein in formulae (II), (III), (IV) and (V): X₁ is chosen fromnitrogen atoms and CR₅ radicals, X₂ is chosen from nitrogen atoms andCR₆ radicals, X₃ is chosen from nitrogen atoms and CR₁₇ radicals, X₄ ischosen from nitrogen atoms and CR₁₈ radicals, Z₁ is chosen from oxygenand sulfur atoms, and NR₈ radicals, Z₂ is chosen from nitrogen atoms andCR₉ atoms, with the proviso that when Z₁ is chosen from NR₈ radicals,then Z₂ is not chosen from CR₉ radicals, such that formula (II) is notan imidazolium ring, Z₃ is chosen from nitrogen atoms and CR₁₂ radicals,Z₄ is chosen from nitrogen atoms and CR₁₃ radicals, the bond a of the5-membered cationic ring of formula (II) is linked to the azo group offormula (I), the bond b of the 6-membered cationic ring of formula (III)is linked to the azo group of formula (I), wherein when p=0, then L ischosen from linear and branched, saturated C₁-C₁₆ hydrocarbon-basedchains, which can form at least one 3- to 6-membered carbon-based ring,wherein at least one carbon atom of the carbon-based chain is optionallyreplaced with an entity chosen from oxygen, nitrogen and sulfur atoms,and from SO₂ groups, and further wherein the carbon atoms of the chainare optionally substituted, independently of each other, with at leastone halogen atom; with the proviso that L does not comprise a peroxidebond or diazo or nitroso radicals, wherein when p=1, then L is chosenfrom saturated and unsaturated, linear and branched C₁-C₁₆hydrocarbon-based chains, which can form at least one 3- to 6-memberedcarbon-based ring, wherein at least one carbon atom of the carbon-basedchain is optionally replaced with an entity chosen from oxygen, nitrogenand sulfur atoms, and from SO₂ groups; with the proviso that L does notcomprise a peroxide bond or diazo or nitroso radicals, R₃, R₄, R₅, R₆,R₇, R₉, R₁₀, R₁₁, R₁₂, R₁₃, R₁₄, R₁₅, R₁₆, R₁₇ and R₁₈, which may beidentical or different, are chosen from hydrogen atoms, saturated andunsaturated, linear and branched C₁-C₁₆ hydrocarbon-based chains, whichcan form at least one 3- to 6-membered carbon-based ring, wherein atleast one carbon atom of the carbon-based chain is optionally replacedwith an entity chosen from oxygen, nitrogen and sulfur atoms, and fromSO₂ groups, and the carbon atoms of the chain are optionallysubstituted, independently of each other, with at least one halogenatom; and with the proviso that R₃, R₄, R₅, R₆, R₇, R₉, R₁₀, R₁₁, R₁₂,R₁₃, R₁₄, R₁₅, R₁₆, R₁₇ and R₁₈ do not comprise a peroxide bond or diazoor nitroso radicals, R₃ with R₄, R₇ with R₉, R₁₀ with R₁₁, R₁₂ with R₁₃and R₁₅ with R₁₆ can optionally form a carbon-based aromatic ring, R₁,R₂ and R₈ are chosen from linear and branched C₁-C₈ alkyl radicalsoptionally substituted with at least one radical chosen from hydroxyl,C₁-C₂ alkoxy, C₂-C₄ (poly)hydroxyalkoxy, amino, C₁-C₂ (di)alkylamino,carboxyl and sulfonic radicals; and optionally substituted phenylradicals, and X is chosen from organic and mineral anions; and at leastone second compartment comprises an oxidizing composition.
 88. Thedicationic diazo compound of formula (I) [W₁—N═N—W₂—W₃—W₄—W₅)_(p)-]₂-L  Formula (I) wherein: p=0 or 1, W₁ is chosen from heteroaromaticradicals of formulae (II) and (III):

W₂ is chosen from carbon-based, pyridine-based and pyridazine-basedaromatic groups of formula (IV):

W₃ and W₅, which may be identical or different, are chosen from —NR₁₄—radicals, and oxygen and nitrogen atoms, W₄ is chosen from saturated andunsaturated, linear and branched C₁-C₁₆ hydrocarbon-based chains, whichcan form at least one 3- to 6-membered carbon-based ring, wherein atleast one carbon atom of the carbon-based chain may optionally bereplaced with an entity chosen from oxygen, nitrogen and sulfur atomsand from SO₂ groups, and further wherein the carbon atoms may optionallybe substituted, independently of each other, with at least one halogenatom, provided that W₄ does not comprise a peroxide bond or diazo ornitroso radicals; piperazine rings; and groups of formula (V):

wherein in formulae (II), (III), (IV) and (V): X₁ is chosen fromnitrogen atoms and CR₅ radicals, X₂ is chosen from nitrogen atoms andCR₆ radicals, X₃ is chosen from nitrogen atoms and CR₁₇ radicals, X₄ ischosen from nitrogen atoms and CR₁₈ radicals, Z₁ is chosen from oxygenand sulfur atoms, and NR₈ radicals, Z₂ is chosen from nitrogen atoms andCR₉ atoms, with the proviso that when Z₁ is chosen from NR₈ radicals,then Z₂ is not chosen from CR₉ radicals, such that formula (II) is notan imidazolium ring, Z₃ is chosen from nitrogen atoms and CR₁₂ radicals,Z₄ is chosen from nitrogen atoms and CR₁₃ radicals, the bond a of the5-membered cationic ring of formula (II) is linked to the azo group offormula (I), the bond b of the 6-membered cationic ring of formula (III)is linked to the azo group of formula (I), wherein when p=0, then L ischosen from linear and branched, saturated C₁-C₁₆ hydrocarbon-basedchains, which can form at least one 3- to 6-membered carbon-based ring,wherein at least one carbon atom of the carbon-based chain is optionallyreplaced with an entity chosen from oxygen, nitrogen and sulfur atomsand from SO₂ groups, and further wherein the carbon atoms of the chainare optionally substituted, independently of each other, with at leastone halogen atom; with the proviso that L does not comprise a peroxidebond or diazo or nitroso radicals, wherein when p=1, then L is chosenfrom saturated and unsaturated, linear and branched C₁-C₁₆hydrocarbon-based chains, which can form at least one 3- to 6-memberedcarbon-based ring, wherein at least one carbon atom of the carbon-basedchain is optionally replaced with an entity chosen from oxygen, nitrogenand sulfur atoms and from SO₂ groups; with the proviso that L does notcomprise a peroxide bond or diazo or nitroso radicals, R₃, R₄, R₅, R₆,R₇, R₉, R₁₀, R₁₁, R₁₂, R₁₃, R₁₄, R₁₅, R₁₆, R₁₇ and R₁₈, which may beidentical or different, are chosen from hydrogen atoms, saturated andunsaturated, linear and branched C₁-C₁₆ hydrocarbon-based chains, whichcan form at least one 3- to 6-membered carbon-based ring, wherein atleast one carbon atom of the carbon-based chain is optionally replacedwith an entity chosen from oxygen, nitrogen and sulfur atoms, and fromSO₂ groups, and the carbon atoms of the chain are optionallysubstituted, independently of each other, with at least one halogenatom; and with the proviso that R₃, R₄, R₅, R₆, R₇, R₉, R₁₀, R₁₁, R₁₂,R₁₃, R₁₄, R₁₅, R₁₆, R₁₇ and R₁₈ do not comprise a peroxide bond or diazoor nitroso radicals, R₃ with R₄, R₇ with R₉, R₁₀ with R₁₁, R₁₂ with R₁₃and R₁₅ with R₁₆ can optionally form a carbon-based aromatic ring, R₁,R₂ and R₈ are chosen from linear and branched C₁-C₈ alkyl radicalsoptionally substituted with at least one radical chosen from hydroxyl,C₁-C₂ alkoxy, C₂-C₄ (poly)hydroxyalkoxy, amino, C₁-C₂ (di)alkylamino,carboxyl and sulfonic radicals; and optionally substituted phenylradicals, and X is chosen from organic and mineral anions.
 89. Thedicationic diazo compound according to claim 88, wherein when p=0, W₃ isan oxygen atom, or W₃ is chosen from —NR₁₄— radicals and L is chosenfrom aryl and heteroaryl radicals optionally substituted with at leastone radical chosen from hydroxyl, C₁-C₂ alkoxy, C₂-C₄(poly)hydroxyalkoxy, amino, C₁-C₂ (di)alkylamino, carboxyl and sulfonicradicals, and halogen atoms.
 90. The dicationic diazo compound accordingto claim 89, wherein the halogen atoms are chosen from chlorine,fluorine or bromine.